I you want to avoid boredom in your painting, then all figures should result in a different silhouette. Let me take the example of the painting Bonjour Monsieur Courbet, by the French painter Gustave Courbet, to illustrate the point.

After I blackened each figure, the characters are all distinct. You could even guess, from the silhouette alone, the mood of each of these character. Courbet, on the right, holds his head high. With his long walking stick, he seems very stable and looks statuesque. The gentleman in the middle is welcoming with his arms open. As for the third gentleman on the left, he respectfully bow his head and looks humble.